TFF / UF-DF simulation

feed -> retentate (concentrated) + permeate

Governing equations

The exact equations the solver works for a tff / uf-df — the same math shown in the app's "Theory" panel, not a black box.

$J$

permeate flux [m/s]

$k$

mass-transfer coefficient [m/s]

$c_w$

wall concentration [kg/m^3]

$c_b$

bulk concentration [kg/m^3]

$\Delta P$

transmembrane pressure [Pa]

$\Delta\pi$

osmotic-pressure difference [Pa]

$\mu$

viscosity [Pa.s]

$R_m$

membrane resistance [1/m]

$M$

product molar mass [kg/mol]

$A_2, A_3$

second and third virial coefficients (measured)

$N$

diavolumes

$\sigma$

rejection of the washed species (0 = free passage)

Parameters

product [component id the membrane retains], product_molar_mass [kg/mol, e.g. 148 for a 148 kDa mAb]; a concentration target — final_concentration [kg/m^3] or concentration_factor [x fold]. Optional: rejection [default 1.0 for the product], rejections [{component: 0-1} for the rest, default 0 so buffer salts pass], tmp [Pa], mass_transfer_coefficient [m/s, set by your crossflow], viscosity, membrane_resistance [1/m], a2/a3 [virial coefficients, measured for your protein in your buffer], c_gel, area [m^2] + batch_time [s] to report the step time, diavolumes + salt_rejection for a diafiltration.

Example flowsheets that use it